includes/Database.php

   1 <?php
   2 /**
   3  * This file deals with MySQL interface functions
   4  * and query specifics/optimisations
   5  */
   6
   7 /** Number of times to re-try an operation in case of deadlock */
   8 define( 'DEADLOCK_TRIES', 4 );
   9 /** Minimum time to wait before retry, in microseconds */
  10 define( 'DEADLOCK_DELAY_MIN', 500000 );
  11 /** Maximum time to wait before retry */
  12 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  13
  14 /******************************************************************************
  15  * Utility classes
  16  *****************************************************************************/
  17
  18 /**
  19  * Utility class.
  20  * @addtogroup Database
  21  */
  22 class DBObject {
  23         public $mData;
  24
  25         function DBObject($data) {
  26                 $this->mData = $data;
  27         }
  28
  29         function isLOB() {
  30                 return false;
  31         }
  32
  33         function data() {
  34                 return $this->mData;
  35         }
  36 };
  37
  38 /**
  39  * Utility class
  40  * @addtogroup Database
  41  *
  42  * This allows us to distinguish a blob from a normal string and an array of strings
  43  */
  44 class Blob {
  45         private $mData;
  46         function __construct($data) {
  47                 $this->mData = $data;
  48         }
  49         function fetch() {
  50                 return $this->mData;
  51         }
  52 };
  53
  54 /**
  55  * Utility class.
  56  * @addtogroup Database
  57  */
  58 class MySQLField {
  59         private $name, $tablename, $default, $max_length, $nullable,
  60                 $is_pk, $is_unique, $is_key, $type;
  61         function __construct ($info) {
  62                 $this->name = $info->name;
  63                 $this->tablename = $info->table;
  64                 $this->default = $info->def;
  65                 $this->max_length = $info->max_length;
  66                 $this->nullable = !$info->not_null;
  67                 $this->is_pk = $info->primary_key;
  68                 $this->is_unique = $info->unique_key;
  69                 $this->is_multiple = $info->multiple_key;
  70                 $this->is_key = ($this->is_pk || $this->is_unique || $this->is_multiple);
  71                 $this->type = $info->type;
  72         }
  73
  74         function name() {
  75                 return $this->name;
  76         }
  77
  78         function tableName() {
  79                 return $this->tableName;
  80         }
  81
  82         function defaultValue() {
  83                 return $this->default;
  84         }
  85
  86         function maxLength() {
  87                 return $this->max_length;
  88         }
  89
  90         function nullable() {
  91                 return $this->nullable;
  92         }
  93
  94         function isKey() {
  95                 return $this->is_key;
  96         }
  97
  98         function isMultipleKey() {
  99                 return $this->is_multiple;
 100         }
 101
 102         function type() {
 103                 return $this->type;
 104         }
 105 }
 106
 107 /******************************************************************************
 108  * Error classes
 109  *****************************************************************************/
 110
 111 /**
 112  * Database error base class
 113  * @addtogroup Database
 114  */
 115 class DBError extends MWException {
 116         public $db;
 117
 118         /**
 119          * Construct a database error
 120          * @param Database $db The database object which threw the error
 121          * @param string $error A simple error message to be used for debugging
 122          */
 123         function __construct( Database &$db, $error ) {
 124                 $this->db =& $db;
 125                 parent::__construct( $error );
 126         }
 127 }
 128
 129 /**
 130  * @addtogroup Database
 131  */
 132 class DBConnectionError extends DBError {
 133         public $error;
 134
 135         function __construct( Database &$db, $error = 'unknown error' ) {
 136                 $msg = 'DB connection error';
 137                 if ( trim( $error ) != '' ) {
 138                         $msg .= ": $error";
 139                 }
 140                 $this->error = $error;
 141                 parent::__construct( $db, $msg );
 142         }
 143
 144         function useOutputPage() {
 145                 // Not likely to work
 146                 return false;
 147         }
 148
 149         function useMessageCache() {
 150                 // Not likely to work
 151                 return false;
 152         }
 153
 154         function getText() {
 155                 return $this->getMessage() . "\n";
 156         }
 157
 158         function getLogMessage() {
 159                 # Don't send to the exception log
 160                 return false;
 161         }
 162
 163         function getPageTitle() {
 164                 global $wgSitename;
 165                 return "$wgSitename has a problem";
 166         }
 167
 168         function getHTML() {
 169                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding;
 170                 global $wgSitename, $wgServer, $wgMessageCache;
 171
 172                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
 173                 # Hard coding strings instead.
 174
 175                 $noconnect = "<p><strong>Sorry! This site is experiencing technical difficulties.</strong></p><p>Try waiting a few minutes and reloading.</p><p><small>(Can't contact the database server: $1)</small></p>";
 176                 $mainpage = 'Main Page';
 177                 $searchdisabled = <<<EOT
 178 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
 179 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
 180 EOT;
 181
 182                 $googlesearch = "
 183 <!-- SiteSearch Google -->
 184 <FORM method=GET action=\"http://www.google.com/search\">
 185 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
 186 <A HREF=\"http://www.google.com/\">
 187 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
 188 border=\"0\" ALT=\"Google\"></A>
 189 </td>
 190 <td>
 191 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
 192 <INPUT type=submit name=btnG VALUE=\"Google Search\">
 193 <font size=-1>
 194 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
 195 <input type='hidden' name='ie' value='$2'>
 196 <input type='hidden' name='oe' value='$2'>
 197 </font>
 198 </td></tr></TABLE>
 199 </FORM>
 200 <!-- SiteSearch Google -->";
 201                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
 202
 203                 # No database access
 204                 if ( is_object( $wgMessageCache ) ) {
 205                         $wgMessageCache->disable();
 206                 }
 207
 208                 if ( trim( $this->error ) == '' ) {
 209                         $this->error = $this->db->getProperty('mServer');
 210                 }
 211
 212                 $text = str_replace( '$1', $this->error, $noconnect );
 213                 $text .= wfGetSiteNotice();
 214
 215                 if($wgUseFileCache) {
 216                         if($wgTitle) {
 217                                 $t =& $wgTitle;
 218                         } else {
 219                                 if($title) {
 220                                         $t = Title::newFromURL( $title );
 221                                 } elseif (@/**/$_REQUEST['search']) {
 222                                         $search = $_REQUEST['search'];
 223                                         return $searchdisabled .
 224                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
 225                                           $wgInputEncoding ), $googlesearch );
 226                                 } else {
 227                                         $t = Title::newFromText( $mainpage );
 228                                 }
 229                         }
 230
 231                         $cache = new HTMLFileCache( $t );
 232                         if( $cache->isFileCached() ) {
 233                                 // @todo, FIXME: $msg is not defined on the next line.
 234                                 $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
 235                                         $cachederror . "</b></p>\n";
 236
 237                                 $tag = '<div id="article">';
 238                                 $text = str_replace(
 239                                         $tag,
 240                                         $tag . $msg,
 241                                         $cache->fetchPageText() );
 242                         }
 243                 }
 244
 245                 return $text;
 246         }
 247 }
 248
 249 /**
 250  * @addtogroup Database
 251  */
 252 class DBQueryError extends DBError {
 253         public $error, $errno, $sql, $fname;
 254
 255         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
 256                 $message = "A database error has occurred\n" .
 257                   "Query: $sql\n" .
 258                   "Function: $fname\n" .
 259                   "Error: $errno $error\n";
 260
 261                 parent::__construct( $db, $message );
 262                 $this->error = $error;
 263                 $this->errno = $errno;
 264                 $this->sql = $sql;
 265                 $this->fname = $fname;
 266         }
 267
 268         function getText() {
 269                 if ( $this->useMessageCache() ) {
 270                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
 271                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
 272                 } else {
 273                         return $this->getMessage();
 274                 }
 275         }
 276
 277         function getSQL() {
 278                 global $wgShowSQLErrors;
 279                 if( !$wgShowSQLErrors ) {
 280                         return $this->msg( 'sqlhidden', 'SQL hidden' );
 281                 } else {
 282                         return $this->sql;
 283                 }
 284         }
 285
 286         function getLogMessage() {
 287                 # Don't send to the exception log
 288                 return false;
 289         }
 290
 291         function getPageTitle() {
 292                 return $this->msg( 'databaseerror', 'Database error' );
 293         }
 294
 295         function getHTML() {
 296                 if ( $this->useMessageCache() ) {
 297                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
 298                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
 299                 } else {
 300                         return nl2br( htmlspecialchars( $this->getMessage() ) );
 301                 }
 302         }
 303 }
 304
 305 /**
 306  * @addtogroup Database
 307  */
 308 class DBUnexpectedError extends DBError {}
 309
 310 /******************************************************************************/
 311
 312 /**
 313  * Database abstraction object
 314  * @addtogroup Database
 315  */
 316 class Database {
 317
 318 #------------------------------------------------------------------------------
 319 # Variables
 320 #------------------------------------------------------------------------------
 321
 322         protected $mLastQuery = '';
 323
 324         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
 325         protected $mOut, $mOpened = false;
 326
 327         protected $mFailFunction;
 328         protected $mTablePrefix;
 329         protected $mFlags;
 330         protected $mTrxLevel = 0;
 331         protected $mErrorCount = 0;
 332         protected $mLBInfo = array();
 333
 334 #------------------------------------------------------------------------------
 335 # Accessors
 336 #------------------------------------------------------------------------------
 337         # These optionally set a variable and return the previous state
 338
 339         /**
 340          * Fail function, takes a Database as a parameter
 341          * Set to false for default, 1 for ignore errors
 342          */
 343         function failFunction( $function = NULL ) {
 344                 return wfSetVar( $this->mFailFunction, $function );
 345         }
 346
 347         /**
 348          * Output page, used for reporting errors
 349          * FALSE means discard output
 350          */
 351         function setOutputPage( $out ) {
 352                 $this->mOut = $out;
 353         }
 354
 355         /**
 356          * Boolean, controls output of large amounts of debug information
 357          */
 358         function debug( $debug = NULL ) {
 359                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
 360         }
 361
 362         /**
 363          * Turns buffering of SQL result sets on (true) or off (false).
 364          * Default is "on" and it should not be changed without good reasons.
 365          */
 366         function bufferResults( $buffer = NULL ) {
 367                 if ( is_null( $buffer ) ) {
 368                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
 369                 } else {
 370                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
 371                 }
 372         }
 373
 374         /**
 375          * Turns on (false) or off (true) the automatic generation and sending
 376          * of a "we're sorry, but there has been a database error" page on
 377          * database errors. Default is on (false). When turned off, the
 378          * code should use lastErrno() and lastError() to handle the
 379          * situation as appropriate.
 380          */
 381         function ignoreErrors( $ignoreErrors = NULL ) {
 382                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
 383         }
 384
 385         /**
 386          * The current depth of nested transactions
 387          * @param $level Integer: , default NULL.
 388          */
 389         function trxLevel( $level = NULL ) {
 390                 return wfSetVar( $this->mTrxLevel, $level );
 391         }
 392
 393         /**
 394          * Number of errors logged, only useful when errors are ignored
 395          */
 396         function errorCount( $count = NULL ) {
 397                 return wfSetVar( $this->mErrorCount, $count );
 398         }
 399
 400         /**
 401          * Properties passed down from the server info array of the load balancer
 402          */
 403         function getLBInfo( $name = NULL ) {
 404                 if ( is_null( $name ) ) {
 405                         return $this->mLBInfo;
 406                 } else {
 407                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 408                                 return $this->mLBInfo[$name];
 409                         } else {
 410                                 return NULL;
 411                         }
 412                 }
 413         }
 414
 415         function setLBInfo( $name, $value = NULL ) {
 416                 if ( is_null( $value ) ) {
 417                         $this->mLBInfo = $name;
 418                 } else {
 419                         $this->mLBInfo[$name] = $value;
 420                 }
 421         }
 422
 423         /**
 424          * Returns true if this database supports (and uses) cascading deletes
 425          */
 426         function cascadingDeletes() {
 427                 return false;
 428         }
 429
 430         /**
 431          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 432          */
 433         function cleanupTriggers() {
 434                 return false;
 435         }
 436
 437         /**
 438          * Returns true if this database is strict about what can be put into an IP field.
 439          * Specifically, it uses a NULL value instead of an empty string.
 440          */
 441         function strictIPs() {
 442                 return false;
 443         }
 444
 445         /**
 446          * Returns true if this database uses timestamps rather than integers
 447         */
 448         function realTimestamps() {
 449                 return false;
 450         }
 451
 452         /**
 453          * Returns true if this database does an implicit sort when doing GROUP BY
 454          */
 455         function implicitGroupby() {
 456                 return true;
 457         }
 458
 459         /**
 460          * Returns true if this database does an implicit order by when the column has an index
 461          * For example: SELECT page_title FROM page LIMIT 1
 462          */
 463         function implicitOrderby() {
 464                 return true;
 465         }
 466
 467         /**
 468          * Returns true if this database can do a native search on IP columns
 469          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 470          */
 471         function searchableIPs() {
 472                 return false;
 473         }
 474
 475         /**
 476          * Returns true if this database can use functional indexes
 477          */
 478         function functionalIndexes() {
 479                 return false;
 480         }
 481
 482         /**#@+
 483          * Get function
 484          */
 485         function lastQuery() { return $this->mLastQuery; }
 486         function isOpen() { return $this->mOpened; }
 487         /**#@-*/
 488
 489         function setFlag( $flag ) {
 490                 $this->mFlags |= $flag;
 491         }
 492
 493         function clearFlag( $flag ) {
 494                 $this->mFlags &= ~$flag;
 495         }
 496
 497         function getFlag( $flag ) {
 498                 return !!($this->mFlags & $flag);
 499         }
 500
 501         /**
 502          * General read-only accessor
 503          */
 504         function getProperty( $name ) {
 505                 return $this->$name;
 506         }
 507
 508 #------------------------------------------------------------------------------
 509 # Other functions
 510 #------------------------------------------------------------------------------
 511
 512         /**@{{
 513          * Constructor.
 514          * @param string $server database server host
 515          * @param string $user database user name
 516          * @param string $password database user password
 517          * @param string $dbname database name
 518          * @param failFunction
 519          * @param $flags
 520          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 521          */
 522         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 523                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 524
 525                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 526                 # Can't get a reference if it hasn't been set yet
 527                 if ( !isset( $wgOut ) ) {
 528                         $wgOut = NULL;
 529                 }
 530                 $this->mOut =& $wgOut;
 531
 532                 $this->mFailFunction = $failFunction;
 533                 $this->mFlags = $flags;
 534
 535                 if ( $this->mFlags & DBO_DEFAULT ) {
 536                         if ( $wgCommandLineMode ) {
 537                                 $this->mFlags &= ~DBO_TRX;
 538                         } else {
 539                                 $this->mFlags |= DBO_TRX;
 540                         }
 541                 }
 542
 543                 /*
 544                 // Faster read-only access
 545                 if ( wfReadOnly() ) {
 546                         $this->mFlags |= DBO_PERSISTENT;
 547                         $this->mFlags &= ~DBO_TRX;
 548                 }*/
 549
 550                 /** Get the default table prefix*/
 551                 if ( $tablePrefix == 'get from global' ) {
 552                         $this->mTablePrefix = $wgDBprefix;
 553                 } else {
 554                         $this->mTablePrefix = $tablePrefix;
 555                 }
 556
 557                 if ( $server ) {
 558                         $this->open( $server, $user, $password, $dbName );
 559                 }
 560         }
 561
 562         /**
 563          * @static
 564          * @param failFunction
 565          * @param $flags
 566          */
 567         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0 )
 568         {
 569                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 570         }
 571
 572         /**
 573          * Usually aborts on failure
 574          * If the failFunction is set to a non-zero integer, returns success
 575          */
 576         function open( $server, $user, $password, $dbName ) {
 577                 global $wguname;
 578                 wfProfileIn( __METHOD__ );
 579
 580                 # Test for missing mysql.so
 581                 # First try to load it
 582                 if (!@extension_loaded('mysql')) {
 583                         @dl('mysql.so');
 584                 }
 585
 586                 # Fail now
 587                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 588                 if ( !function_exists( 'mysql_connect' ) ) {
 589                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 590                 }
 591
 592                 $this->close();
 593                 $this->mServer = $server;
 594                 $this->mUser = $user;
 595                 $this->mPassword = $password;
 596                 $this->mDBname = $dbName;
 597
 598                 $success = false;
 599
 600                 wfProfileIn("dbconnect-$server");
 601
 602                 # LIVE PATCH by Tim, ask Domas for why: retry loop
 603                 $this->mConn = false;
 604                 $max = 3;
 605                 for ( $i = 0; $i < $max && !$this->mConn; $i++ ) {
 606                         if ( $i > 1 ) {
 607                                 usleep( 1000 );
 608                         }
 609                         if ( $this->mFlags & DBO_PERSISTENT ) {
 610                                 @/**/$this->mConn = mysql_pconnect( $server, $user, $password );
 611                         } else {
 612                                 # Create a new connection...
 613                                 @/**/$this->mConn = mysql_connect( $server, $user, $password, true );
 614                         }
 615                         if ($this->mConn === false) {
 616                                 #$iplus = $i + 1;
 617                                 #wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 618                         }
 619                 }
 620
 621                 wfProfileOut("dbconnect-$server");
 622
 623                 if ( $dbName != '' ) {
 624                         if ( $this->mConn !== false ) {
 625                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 626                                 if ( !$success ) {
 627                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 628                                                 "from client host {$wguname['nodename']}\n";
 629                                         wfLogDBError(" Error selecting database $dbName on server {$this->mServer} \n");
 630                                         wfDebug( $error );
 631                                 }
 632                         } else {
 633                                 wfDebug( "DB connection error\n" );
 634                                 wfDebug( "Server: $server, User: $user, Password: " .
 635                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 636                                 $success = false;
 637                         }
 638                 } else {
 639                         # Delay USE query
 640                         $success = (bool)$this->mConn;
 641                 }
 642
 643                 if ( $success ) {
 644                         $version = $this->getServerVersion();
 645                         if ( version_compare( $version, '4.1' ) >= 0 ) {
 646                                 // Tell the server we're communicating with it in UTF-8.
 647                                 // This may engage various charset conversions.
 648                                 global $wgDBmysql5;
 649                                 if( $wgDBmysql5 ) {
 650                                         $this->query( 'SET NAMES utf8', __METHOD__ );
 651                                 }
 652                                 // Turn off strict mode
 653                                 $this->query( "SET sql_mode = ''", __METHOD__ );
 654                         }
 655
 656                         // Turn off strict mode if it is on
 657                 } else {
 658                         $this->reportConnectionError();
 659                 }
 660
 661                 $this->mOpened = $success;
 662                 wfProfileOut( __METHOD__ );
 663                 return $success;
 664         }
 665         /**@}}*/
 666
 667         /**
 668          * Closes a database connection.
 669          * if it is open : commits any open transactions
 670          *
 671          * @return bool operation success. true if already closed.
 672          */
 673         function close()
 674         {
 675                 $this->mOpened = false;
 676                 if ( $this->mConn ) {
 677                         if ( $this->trxLevel() ) {
 678                                 $this->immediateCommit();
 679                         }
 680                         return mysql_close( $this->mConn );
 681                 } else {
 682                         return true;
 683                 }
 684         }
 685
 686         /**
 687          * @param string $error fallback error message, used if none is given by MySQL
 688          */
 689         function reportConnectionError( $error = 'Unknown error' ) {
 690                 $myError = $this->lastError();
 691                 if ( $myError ) {
 692                         $error = $myError;
 693                 }
 694
 695                 if ( $this->mFailFunction ) {
 696                         # Legacy error handling method
 697                         if ( !is_int( $this->mFailFunction ) ) {
 698                                 $ff = $this->mFailFunction;
 699                                 $ff( $this, $error );
 700                         }
 701                 } else {
 702                         # New method
 703                         wfLogDBError( "Connection error: $error\n" );
 704                         throw new DBConnectionError( $this, $error );
 705                 }
 706         }
 707
 708         /**
 709          * Usually aborts on failure.  If errors are explicitly ignored, returns success.
 710          *
 711          * @param  $sql        String: SQL query
 712          * @param  $fname      String: Name of the calling function, for profiling/SHOW PROCESSLIST
 713          *     comment (you can use __METHOD__ or add some extra info)
 714          * @param  $tempIgnore Bool:   Whether to avoid throwing an exception on errors...
 715          *     maybe best to catch the exception instead?
 716          * @return true for a successful write query, ResultWrapper object for a successful read query,
 717          *     or false on failure if $tempIgnore set
 718          * @throws DBQueryError Thrown when the database returns an error of any kind
 719          */
 720         public function query( $sql, $fname = '', $tempIgnore = false ) {
 721                 global $wgProfiling;
 722
 723                 if ( $wgProfiling ) {
 724                         # generalizeSQL will probably cut down the query to reasonable
 725                         # logging size most of the time. The substr is really just a sanity check.
 726
 727                         # Who's been wasting my precious column space? -- TS
 728                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 729
 730                         if ( is_null( $this->getLBInfo( 'master' ) ) ) {
 731                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 732                                 $totalProf = 'Database::query';
 733                         } else {
 734                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 735                                 $totalProf = 'Database::query-master';
 736                         }
 737                         wfProfileIn( $totalProf );
 738                         wfProfileIn( $queryProf );
 739                 }
 740
 741                 $this->mLastQuery = $sql;
 742
 743                 # Add a comment for easy SHOW PROCESSLIST interpretation
 744                 #if ( $fname ) {
 745                         global $wgUser;
 746                         if ( is_object( $wgUser ) && !($wgUser instanceof StubObject) ) {
 747                                 $userName = $wgUser->getName();
 748                                 if ( mb_strlen( $userName ) > 15 ) {
 749                                         $userName = mb_substr( $userName, 0, 15 ) . '...';
 750                                 }
 751                                 $userName = str_replace( '/', '', $userName );
 752                         } else {
 753                                 $userName = '';
 754                         }
 755                         $commentedSql = preg_replace('/\s/', " /* $fname $userName */ ", $sql, 1);
 756                 #} else {
 757                 #       $commentedSql = $sql;
 758                 #}
 759
 760                 # If DBO_TRX is set, start a transaction
 761                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 762                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK') {
 763                         // avoid establishing transactions for SHOW and SET statements too -
 764                         // that would delay transaction initializations to once connection
 765                         // is really used by application
 766                         $sqlstart = substr($sql,0,10); // very much worth it, benchmark certified(tm)
 767                         if (strpos($sqlstart,"SHOW ")!==0 and strpos($sqlstart,"SET ")!==0)
 768                                 $this->begin();
 769                 }
 770
 771                 if ( $this->debug() ) {
 772                         $sqlx = substr( $commentedSql, 0, 500 );
 773                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 774                         wfDebug( "SQL: $sqlx\n" );
 775                 }
 776
 777                 # Do the query and handle errors
 778                 $ret = $this->doQuery( $commentedSql );
 779
 780                 # Try reconnecting if the connection was lost
 781                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 782                         # Transaction is gone, like it or not
 783                         $this->mTrxLevel = 0;
 784                         wfDebug( "Connection lost, reconnecting...\n" );
 785                         if ( $this->ping() ) {
 786                                 wfDebug( "Reconnected\n" );
 787                                 $sqlx = substr( $commentedSql, 0, 500 );
 788                                 $sqlx = strtr( $sqlx, "\t\n", '  ' );
 789                                 global $wgRequestTime;
 790                                 $elapsed = round( microtime(true) - $wgRequestTime, 3 );
 791                                 wfLogDBError( "Connection lost and reconnected after {$elapsed}s, query: $sqlx\n" );
 792                                 $ret = $this->doQuery( $commentedSql );
 793                         } else {
 794                                 wfDebug( "Failed\n" );
 795                         }
 796                 }
 797
 798                 if ( false === $ret ) {
 799                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 800                 }
 801
 802                 if ( $wgProfiling ) {
 803                         wfProfileOut( $queryProf );
 804                         wfProfileOut( $totalProf );
 805                 }
 806                 return $this->resultObject( $ret );
 807         }
 808
 809         /**
 810          * The DBMS-dependent part of query()
 811          * @param  $sql String: SQL query.
 812          * @return Result object to feed to fetchObject, fetchRow, ...; or false on failure
 813          * @access private
 814          */
 815         /*private*/ function doQuery( $sql ) {
 816                 if( $this->bufferResults() ) {
 817                         $ret = mysql_query( $sql, $this->mConn );
 818                 } else {
 819                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 820                 }
 821                 return $ret;
 822         }
 823
 824         /**
 825          * @param $error
 826          * @param $errno
 827          * @param $sql
 828          * @param string $fname
 829          * @param bool $tempIgnore
 830          */
 831         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 832                 global $wgCommandLineMode;
 833                 # Ignore errors during error handling to avoid infinite recursion
 834                 $ignore = $this->ignoreErrors( true );
 835                 ++$this->mErrorCount;
 836
 837                 if( $ignore || $tempIgnore ) {
 838                         wfDebug("SQL ERROR (ignored): $error\n");
 839                         $this->ignoreErrors( $ignore );
 840                 } else {
 841                         $sql1line = str_replace( "\n", "\\n", $sql );
 842                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 843                         wfDebug("SQL ERROR: " . $error . "\n");
 844                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 845                 }
 846         }
 847
 848
 849         /**
 850          * Intended to be compatible with the PEAR::DB wrapper functions.
 851          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 852          *
 853          * ? = scalar value, quoted as necessary
 854          * ! = raw SQL bit (a function for instance)
 855          * & = filename; reads the file and inserts as a blob
 856          *     (we don't use this though...)
 857          */
 858         function prepare( $sql, $func = 'Database::prepare' ) {
 859                 /* MySQL doesn't support prepared statements (yet), so just
 860                    pack up the query for reference. We'll manually replace
 861                    the bits later. */
 862                 return array( 'query' => $sql, 'func' => $func );
 863         }
 864
 865         function freePrepared( $prepared ) {
 866                 /* No-op for MySQL */
 867         }
 868
 869         /**
 870          * Execute a prepared query with the various arguments
 871          * @param string $prepared the prepared sql
 872          * @param mixed $args Either an array here, or put scalars as varargs
 873          */
 874         function execute( $prepared, $args = null ) {
 875                 if( !is_array( $args ) ) {
 876                         # Pull the var args
 877                         $args = func_get_args();
 878                         array_shift( $args );
 879                 }
 880                 $sql = $this->fillPrepared( $prepared['query'], $args );
 881                 return $this->query( $sql, $prepared['func'] );
 882         }
 883
 884         /**
 885          * Prepare & execute an SQL statement, quoting and inserting arguments
 886          * in the appropriate places.
 887          * @param string $query
 888          * @param string $args ...
 889          */
 890         function safeQuery( $query, $args = null ) {
 891                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 892                 if( !is_array( $args ) ) {
 893                         # Pull the var args
 894                         $args = func_get_args();
 895                         array_shift( $args );
 896                 }
 897                 $retval = $this->execute( $prepared, $args );
 898                 $this->freePrepared( $prepared );
 899                 return $retval;
 900         }
 901
 902         /**
 903          * For faking prepared SQL statements on DBs that don't support
 904          * it directly.
 905          * @param string $preparedSql - a 'preparable' SQL statement
 906          * @param array $args - array of arguments to fill it with
 907          * @return string executable SQL
 908          */
 909         function fillPrepared( $preparedQuery, $args ) {
 910                 reset( $args );
 911                 $this->preparedArgs =& $args;
 912                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 913                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 914         }
 915
 916         /**
 917          * preg_callback func for fillPrepared()
 918          * The arguments should be in $this->preparedArgs and must not be touched
 919          * while we're doing this.
 920          *
 921          * @param array $matches
 922          * @return string
 923          * @private
 924          */
 925         function fillPreparedArg( $matches ) {
 926                 switch( $matches[1] ) {
 927                         case '\\?': return '?';
 928                         case '\\!': return '!';
 929                         case '\\&': return '&';
 930                 }
 931                 list( /* $n */ , $arg ) = each( $this->preparedArgs );
 932                 switch( $matches[1] ) {
 933                         case '?': return $this->addQuotes( $arg );
 934                         case '!': return $arg;
 935                         case '&':
 936                                 # return $this->addQuotes( file_get_contents( $arg ) );
 937                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 938                         default:
 939                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 940                 }
 941         }
 942
 943         /**#@+
 944          * @param mixed $res A SQL result
 945          */
 946         /**
 947          * Free a result object
 948          */
 949         function freeResult( $res ) {
 950                 if ( $res instanceof ResultWrapper ) {
 951                         $res = $res->result;
 952                 }
 953                 if ( !@/**/mysql_free_result( $res ) ) {
 954                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 955                 }
 956         }
 957
 958         /**
 959          * Fetch the next row from the given result object, in object form.
 960          * Fields can be retrieved with $row->fieldname, with fields acting like
 961          * member variables.
 962          *
 963          * @param $res SQL result object as returned from Database::query(), etc.
 964          * @return MySQL row object
 965          * @throws DBUnexpectedError Thrown if the database returns an error
 966          */
 967         function fetchObject( $res ) {
 968                 if ( $res instanceof ResultWrapper ) {
 969                         $res = $res->result;
 970                 }
 971                 @/**/$row = mysql_fetch_object( $res );
 972                 if( $this->lastErrno() ) {
 973                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 974                 }
 975                 return $row;
 976         }
 977
 978         /**
 979          * Fetch the next row from the given result object, in associative array
 980          * form.  Fields are retrieved with $row['fieldname'].
 981          *
 982          * @param $res SQL result object as returned from Database::query(), etc.
 983          * @return MySQL row object
 984          * @throws DBUnexpectedError Thrown if the database returns an error
 985          */
 986         function fetchRow( $res ) {
 987                 if ( $res instanceof ResultWrapper ) {
 988                         $res = $res->result;
 989                 }
 990                 @/**/$row = mysql_fetch_array( $res );
 991                 if ( $this->lastErrno() ) {
 992                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 993                 }
 994                 return $row;
 995         }
 996
 997         /**
 998          * Get the number of rows in a result object
 999          */
1000         function numRows( $res ) {
1001                 if ( $res instanceof ResultWrapper ) {
1002                         $res = $res->result;
1003                 }
1004                 @/**/$n = mysql_num_rows( $res );
1005                 if( $this->lastErrno() ) {
1006                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
1007                 }
1008                 return $n;
1009         }
1010
1011         /**
1012          * Get the number of fields in a result object
1013          * See documentation for mysql_num_fields()
1014          */
1015         function numFields( $res ) {
1016                 if ( $res instanceof ResultWrapper ) {
1017                         $res = $res->result;
1018                 }
1019                 return mysql_num_fields( $res );
1020         }
1021
1022         /**
1023          * Get a field name in a result object
1024          * See documentation for mysql_field_name():
1025          * http://www.php.net/mysql_field_name
1026          */
1027         function fieldName( $res, $n ) {
1028                 if ( $res instanceof ResultWrapper ) {
1029                         $res = $res->result;
1030                 }
1031                 return mysql_field_name( $res, $n );
1032         }
1033
1034         /**
1035          * Get the inserted value of an auto-increment row
1036          *
1037          * The value inserted should be fetched from nextSequenceValue()
1038          *
1039          * Example:
1040          * $id = $dbw->nextSequenceValue('page_page_id_seq');
1041          * $dbw->insert('page',array('page_id' => $id));
1042          * $id = $dbw->insertId();
1043          */
1044         function insertId() { return mysql_insert_id( $this->mConn ); }
1045
1046         /**
1047          * Change the position of the cursor in a result object
1048          * See mysql_data_seek()
1049          */
1050         function dataSeek( $res, $row ) {
1051                 if ( $res instanceof ResultWrapper ) {
1052                         $res = $res->result;
1053                 }
1054                 return mysql_data_seek( $res, $row );
1055         }
1056
1057         /**
1058          * Get the last error number
1059          * See mysql_errno()
1060          */
1061         function lastErrno() {
1062                 if ( $this->mConn ) {
1063                         return mysql_errno( $this->mConn );
1064                 } else {
1065                         return mysql_errno();
1066                 }
1067         }
1068
1069         /**
1070          * Get a description of the last error
1071          * See mysql_error() for more details
1072          */
1073         function lastError() {
1074                 if ( $this->mConn ) {
1075                         # Even if it's non-zero, it can still be invalid
1076                         wfSuppressWarnings();
1077                         $error = mysql_error( $this->mConn );
1078                         if ( !$error ) {
1079                                 $error = mysql_error();
1080                         }
1081                         wfRestoreWarnings();
1082                 } else {
1083                         $error = mysql_error();
1084                 }
1085                 if( $error ) {
1086                         $error .= ' (' . $this->mServer . ')';
1087                 }
1088                 return $error;
1089         }
1090         /**
1091          * Get the number of rows affected by the last write query
1092          * See mysql_affected_rows() for more details
1093          */
1094         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
1095         /**#@-*/ // end of template : @param $result
1096
1097         /**
1098          * Simple UPDATE wrapper
1099          * Usually aborts on failure
1100          * If errors are explicitly ignored, returns success
1101          *
1102          * This function exists for historical reasons, Database::update() has a more standard
1103          * calling convention and feature set
1104          */
1105         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
1106         {
1107                 $table = $this->tableName( $table );
1108                 $sql = "UPDATE $table SET $var = '" .
1109                   $this->strencode( $value ) . "' WHERE ($cond)";
1110                 return (bool)$this->query( $sql, $fname );
1111         }
1112
1113         /**
1114          * Simple SELECT wrapper, returns a single field, input must be encoded
1115          * Usually aborts on failure
1116          * If errors are explicitly ignored, returns FALSE on failure
1117          */
1118         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
1119                 if ( !is_array( $options ) ) {
1120                         $options = array( $options );
1121                 }
1122                 $options['LIMIT'] = 1;
1123
1124                 $res = $this->select( $table, $var, $cond, $fname, $options );
1125                 if ( $res === false || !$this->numRows( $res ) ) {
1126                         return false;
1127                 }
1128                 $row = $this->fetchRow( $res );
1129                 if ( $row !== false ) {
1130                         $this->freeResult( $res );
1131                         return $row[0];
1132                 } else {
1133                         return false;
1134                 }
1135         }
1136
1137         /**
1138          * Returns an optional USE INDEX clause to go after the table, and a
1139          * string to go at the end of the query
1140          *
1141          * @private
1142          *
1143          * @param array $options an associative array of options to be turned into
1144          *              an SQL query, valid keys are listed in the function.
1145          * @return array
1146          */
1147         function makeSelectOptions( $options ) {
1148                 $preLimitTail = $postLimitTail = '';
1149                 $startOpts = '';
1150
1151                 $noKeyOptions = array();
1152                 foreach ( $options as $key => $option ) {
1153                         if ( is_numeric( $key ) ) {
1154                                 $noKeyOptions[$option] = true;
1155                         }
1156                 }
1157
1158                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
1159                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
1160                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
1161
1162                 //if (isset($options['LIMIT'])) {
1163                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
1164                 //              isset($options['OFFSET']) ? $options['OFFSET']
1165                 //              : false);
1166                 //}
1167
1168                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $postLimitTail .= ' FOR UPDATE';
1169                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $postLimitTail .= ' LOCK IN SHARE MODE';
1170                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
1171
1172                 # Various MySQL extensions
1173                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
1174                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
1175                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
1176                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
1177                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
1178                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
1179                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
1180                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
1181
1182                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
1183                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
1184                 } else {
1185                         $useIndex = '';
1186                 }
1187
1188                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
1189         }
1190
1191         /**
1192          * SELECT wrapper
1193          *
1194          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
1195          * @param mixed  $vars    Array or string, field name(s) to be retrieved
1196          * @param mixed  $conds   Array or string, condition(s) for WHERE
1197          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
1198          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
1199          *                        see Database::makeSelectOptions code for list of supported stuff
1200          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
1201          */
1202         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
1203         {
1204                 if( is_array( $vars ) ) {
1205                         $vars = implode( ',', $vars );
1206                 }
1207                 if( !is_array( $options ) ) {
1208                         $options = array( $options );
1209                 }
1210                 if( is_array( $table ) ) {
1211                         if ( isset( $options['USE INDEX'] ) && is_array( $options['USE INDEX'] ) )
1212                                 $from = ' FROM ' . $this->tableNamesWithUseIndex( $table, $options['USE INDEX'] );
1213                         else
1214                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
1215                 } elseif ($table!='') {
1216                         if ($table{0}==' ') {
1217                                 $from = ' FROM ' . $table;
1218                         } else {
1219                                 $from = ' FROM ' . $this->tableName( $table );
1220                         }
1221                 } else {
1222                         $from = '';
1223                 }
1224
1225                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) = $this->makeSelectOptions( $options );
1226
1227                 if( !empty( $conds ) ) {
1228                         if ( is_array( $conds ) ) {
1229                                 $conds = $this->makeList( $conds, LIST_AND );
1230                         }
1231                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
1232                 } else {
1233                         $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
1234                 }
1235
1236                 if (isset($options['LIMIT']))
1237                         $sql = $this->limitResult($sql, $options['LIMIT'],
1238                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
1239                 $sql = "$sql $postLimitTail";
1240
1241                 if (isset($options['EXPLAIN'])) {
1242                         $sql = 'EXPLAIN ' . $sql;
1243                 }
1244                 return $this->query( $sql, $fname );
1245         }
1246
1247         /**
1248          * Single row SELECT wrapper
1249          * Aborts or returns FALSE on error
1250          *
1251          * $vars: the selected variables
1252          * $conds: a condition map, terms are ANDed together.
1253          *   Items with numeric keys are taken to be literal conditions
1254          * Takes an array of selected variables, and a condition map, which is ANDed
1255          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
1256          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
1257          * $obj- >page_id is the ID of the Astronomy article
1258          *
1259          * @todo migrate documentation to phpdocumentor format
1260          */
1261         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
1262                 $options['LIMIT'] = 1;
1263                 $res = $this->select( $table, $vars, $conds, $fname, $options );
1264                 if ( $res === false )
1265                         return false;
1266                 if ( !$this->numRows($res) ) {
1267                         $this->freeResult($res);
1268                         return false;
1269                 }
1270                 $obj = $this->fetchObject( $res );
1271                 $this->freeResult( $res );
1272                 return $obj;
1273
1274         }
1275
1276         /**
1277          * Estimate rows in dataset
1278          * Returns estimated count, based on EXPLAIN output
1279          * Takes same arguments as Database::select()
1280          */
1281
1282         function estimateRowCount( $table, $vars='*', $conds='', $fname = 'Database::estimateRowCount', $options = array() ) {
1283                 $options['EXPLAIN']=true;
1284                 $res = $this->select ($table, $vars, $conds, $fname, $options );
1285                 if ( $res === false )
1286                         return false;
1287                 if (!$this->numRows($res)) {
1288                         $this->freeResult($res);
1289                         return 0;
1290                 }
1291
1292                 $rows=1;
1293
1294                 while( $plan = $this->fetchObject( $res ) ) {
1295                         $rows *= ($plan->rows > 0)?$plan->rows:1; // avoid resetting to zero
1296                 }
1297
1298                 $this->freeResult($res);
1299                 return $rows;
1300         }
1301
1302
1303         /**
1304          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1305          * It's only slightly flawed. Don't use for anything important.
1306          *
1307          * @param string $sql A SQL Query
1308          * @static
1309          */
1310         static function generalizeSQL( $sql ) {
1311                 # This does the same as the regexp below would do, but in such a way
1312                 # as to avoid crashing php on some large strings.
1313                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1314
1315                 $sql = str_replace ( "\\\\", '', $sql);
1316                 $sql = str_replace ( "\\'", '', $sql);
1317                 $sql = str_replace ( "\\\"", '', $sql);
1318                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1319                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1320
1321                 # All newlines, tabs, etc replaced by single space
1322                 $sql = preg_replace ( '/\s+/', ' ', $sql);
1323
1324                 # All numbers => N
1325                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1326
1327                 return $sql;
1328         }
1329
1330         /**
1331          * Determines whether a field exists in a table
1332          * Usually aborts on failure
1333          * If errors are explicitly ignored, returns NULL on failure
1334          */
1335         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1336                 $table = $this->tableName( $table );
1337                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1338                 if ( !$res ) {
1339                         return NULL;
1340                 }
1341
1342                 $found = false;
1343
1344                 while ( $row = $this->fetchObject( $res ) ) {
1345                         if ( $row->Field == $field ) {
1346                                 $found = true;
1347                                 break;
1348                         }
1349                 }
1350                 return $found;
1351         }
1352
1353         /**
1354          * Determines whether an index exists
1355          * Usually aborts on failure
1356          * If errors are explicitly ignored, returns NULL on failure
1357          */
1358         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1359                 $info = $this->indexInfo( $table, $index, $fname );
1360                 if ( is_null( $info ) ) {
1361                         return NULL;
1362                 } else {
1363                         return $info !== false;
1364                 }
1365         }
1366
1367
1368         /**
1369          * Get information about an index into an object
1370          * Returns false if the index does not exist
1371          */
1372         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1373                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1374                 # SHOW INDEX should work for 3.x and up:
1375                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1376                 $table = $this->tableName( $table );
1377                 $sql = 'SHOW INDEX FROM '.$table;
1378                 $res = $this->query( $sql, $fname );
1379                 if ( !$res ) {
1380                         return NULL;
1381                 }
1382
1383                 $result = array();
1384                 while ( $row = $this->fetchObject( $res ) ) {
1385                         if ( $row->Key_name == $index ) {
1386                                 $result[] = $row;
1387                         }
1388                 }
1389                 $this->freeResult($res);
1390
1391                 return empty($result) ? false : $result;
1392         }
1393
1394         /**
1395          * Query whether a given table exists
1396          */
1397         function tableExists( $table ) {
1398                 $table = $this->tableName( $table );
1399                 $old = $this->ignoreErrors( true );
1400                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1401                 $this->ignoreErrors( $old );
1402                 if( $res ) {
1403                         $this->freeResult( $res );
1404                         return true;
1405                 } else {
1406                         return false;
1407                 }
1408         }
1409
1410         /**
1411          * mysql_fetch_field() wrapper
1412          * Returns false if the field doesn't exist
1413          *
1414          * @param $table
1415          * @param $field
1416          */
1417         function fieldInfo( $table, $field ) {
1418                 $table = $this->tableName( $table );
1419                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1420                 $n = mysql_num_fields( $res->result );
1421                 for( $i = 0; $i < $n; $i++ ) {
1422                         $meta = mysql_fetch_field( $res->result, $i );
1423                         if( $field == $meta->name ) {
1424                                 return new MySQLField($meta);
1425                         }
1426                 }
1427                 return false;
1428         }
1429
1430         /**
1431          * mysql_field_type() wrapper
1432          */
1433         function fieldType( $res, $index ) {
1434                 if ( $res instanceof ResultWrapper ) {
1435                         $res = $res->result;
1436                 }
1437                 return mysql_field_type( $res, $index );
1438         }
1439
1440         /**
1441          * Determines if a given index is unique
1442          */
1443         function indexUnique( $table, $index ) {
1444                 $indexInfo = $this->indexInfo( $table, $index );
1445                 if ( !$indexInfo ) {
1446                         return NULL;
1447                 }
1448                 return !$indexInfo[0]->Non_unique;
1449         }
1450
1451         /**
1452          * INSERT wrapper, inserts an array into a table
1453          *
1454          * $a may be a single associative array, or an array of these with numeric keys, for
1455          * multi-row insert.
1456          *
1457          * Usually aborts on failure
1458          * If errors are explicitly ignored, returns success
1459          */
1460         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1461                 # No rows to insert, easy just return now
1462                 if ( !count( $a ) ) {
1463                         return true;
1464                 }
1465
1466                 $table = $this->tableName( $table );
1467                 if ( !is_array( $options ) ) {
1468                         $options = array( $options );
1469                 }
1470                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1471                         $multi = true;
1472                         $keys = array_keys( $a[0] );
1473                 } else {
1474                         $multi = false;
1475                         $keys = array_keys( $a );
1476                 }
1477
1478                 $sql = 'INSERT ' . implode( ' ', $options ) .
1479                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1480
1481                 if ( $multi ) {
1482                         $first = true;
1483                         foreach ( $a as $row ) {
1484                                 if ( $first ) {
1485                                         $first = false;
1486                                 } else {
1487                                         $sql .= ',';
1488                                 }
1489                                 $sql .= '(' . $this->makeList( $row ) . ')';
1490                         }
1491                 } else {
1492                         $sql .= '(' . $this->makeList( $a ) . ')';
1493                 }
1494                 return (bool)$this->query( $sql, $fname );
1495         }
1496
1497         /**
1498          * Make UPDATE options for the Database::update function
1499          *
1500          * @private
1501          * @param array $options The options passed to Database::update
1502          * @return string
1503          */
1504         function makeUpdateOptions( $options ) {
1505                 if( !is_array( $options ) ) {
1506                         $options = array( $options );
1507                 }
1508                 $opts = array();
1509                 if ( in_array( 'LOW_PRIORITY', $options ) )
1510                         $opts[] = $this->lowPriorityOption();
1511                 if ( in_array( 'IGNORE', $options ) )
1512                         $opts[] = 'IGNORE';
1513                 return implode(' ', $opts);
1514         }
1515
1516         /**
1517          * UPDATE wrapper, takes a condition array and a SET array
1518          *
1519          * @param string $table  The table to UPDATE
1520          * @param array  $values An array of values to SET
1521          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1522          * @param string $fname  The Class::Function calling this function
1523          *                       (for the log)
1524          * @param array  $options An array of UPDATE options, can be one or
1525          *                        more of IGNORE, LOW_PRIORITY
1526          * @return bool
1527          */
1528         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1529                 $table = $this->tableName( $table );
1530                 $opts = $this->makeUpdateOptions( $options );
1531                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1532                 if ( $conds != '*' ) {
1533                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1534                 }
1535                 return $this->query( $sql, $fname );
1536         }
1537
1538         /**
1539          * Makes an encoded list of strings from an array
1540          * $mode:
1541          *        LIST_COMMA         - comma separated, no field names
1542          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1543          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1544          *        LIST_SET           - comma separated with field names, like a SET clause
1545          *        LIST_NAMES         - comma separated field names
1546          */
1547         function makeList( $a, $mode = LIST_COMMA ) {
1548                 if ( !is_array( $a ) ) {
1549                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1550                 }
1551
1552                 $first = true;
1553                 $list = '';
1554                 foreach ( $a as $field => $value ) {
1555                         if ( !$first ) {
1556                                 if ( $mode == LIST_AND ) {
1557                                         $list .= ' AND ';
1558                                 } elseif($mode == LIST_OR) {
1559                                         $list .= ' OR ';
1560                                 } else {
1561                                         $list .= ',';
1562                                 }
1563                         } else {
1564                                 $first = false;
1565                         }
1566                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1567                                 $list .= "($value)";
1568                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1569                                 $list .= "$value";
1570                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
1571                                 if( count( $value ) == 0 ) {
1572                                         // Empty input... or should this throw an error?
1573                                         $list .= '0';
1574                                 } elseif( count( $value ) == 1 ) {
1575                                         // Special-case single values, as IN isn't terribly efficient
1576                                         $list .= $field." = ".$this->addQuotes( $value[0] );
1577                                 } else {
1578                                         $list .= $field." IN (".$this->makeList($value).") ";
1579                                 }
1580                         } elseif( is_null($value) ) {
1581                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1582                                         $list .= "$field IS ";
1583                                 } elseif ( $mode == LIST_SET ) {
1584                                         $list .= "$field = ";
1585                                 }
1586                                 $list .= 'NULL';
1587                         } else {
1588                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1589                                         $list .= "$field = ";
1590                                 }
1591                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1592                         }
1593                 }
1594                 return $list;
1595         }
1596
1597         /**
1598          * Change the current database
1599          */
1600         function selectDB( $db ) {
1601                 $this->mDBname = $db;
1602                 return mysql_select_db( $db, $this->mConn );
1603         }
1604
1605         /**
1606          * Format a table name ready for use in constructing an SQL query
1607          *
1608          * This does two important things: it quotes table names which as necessary,
1609          * and it adds a table prefix if there is one.
1610          *
1611          * All functions of this object which require a table name call this function
1612          * themselves. Pass the canonical name to such functions. This is only needed
1613          * when calling query() directly.
1614          *
1615          * @param string $name database table name
1616          */
1617         function tableName( $name ) {
1618                 global $wgSharedDB;
1619                 # Skip quoted literals
1620                 if ( $name{0} != '`' ) {
1621                         if ( $this->mTablePrefix !== '' &&  strpos( $name, '.' ) === false ) {
1622                                 $name = "{$this->mTablePrefix}$name";
1623                         }
1624                         if ( isset( $wgSharedDB ) && "{$this->mTablePrefix}user" == $name ) {
1625                                 $name = "`$wgSharedDB`.`$name`";
1626                         } else {
1627                                 # Standard quoting
1628                                 $name = "`$name`";
1629                         }
1630                 }
1631                 return $name;
1632         }
1633
1634         /**
1635          * Fetch a number of table names into an array
1636          * This is handy when you need to construct SQL for joins
1637          *
1638          * Example:
1639          * extract($dbr->tableNames('user','watchlist'));
1640          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1641          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1642          */
1643         public function tableNames() {
1644                 $inArray = func_get_args();
1645                 $retVal = array();
1646                 foreach ( $inArray as $name ) {
1647                         $retVal[$name] = $this->tableName( $name );
1648                 }
1649                 return $retVal;
1650         }
1651
1652         /**
1653          * Fetch a number of table names into an zero-indexed numerical array
1654          * This is handy when you need to construct SQL for joins
1655          *
1656          * Example:
1657          * list( $user, $watchlist ) = $dbr->tableNamesN('user','watchlist');
1658          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1659          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1660          */
1661         public function tableNamesN() {
1662                 $inArray = func_get_args();
1663                 $retVal = array();
1664                 foreach ( $inArray as $name ) {
1665                         $retVal[] = $this->tableName( $name );
1666                 }
1667                 return $retVal;
1668         }
1669
1670         /**
1671          * @private
1672          */
1673         function tableNamesWithUseIndex( $tables, $use_index ) {
1674                 $ret = array();
1675
1676                 foreach ( $tables as $table )
1677                         if ( @$use_index[$table] !== null )
1678                                 $ret[] = $this->tableName( $table ) . ' ' . $this->useIndexClause( implode( ',', (array)$use_index[$table] ) );
1679                         else
1680                                 $ret[] = $this->tableName( $table );
1681
1682                 return implode( ',', $ret );
1683         }
1684
1685         /**
1686          * Wrapper for addslashes()
1687          * @param string $s String to be slashed.
1688          * @return string slashed string.
1689          */
1690         function strencode( $s ) {
1691                 return mysql_real_escape_string( $s, $this->mConn );
1692         }
1693
1694         /**
1695          * If it's a string, adds quotes and backslashes
1696          * Otherwise returns as-is
1697          */
1698         function addQuotes( $s ) {
1699                 if ( is_null( $s ) ) {
1700                         return 'NULL';
1701                 } else {
1702                         # This will also quote numeric values. This should be harmless,
1703                         # and protects against weird problems that occur when they really
1704                         # _are_ strings such as article titles and string->number->string
1705                         # conversion is not 1:1.
1706                         return "'" . $this->strencode( $s ) . "'";
1707                 }
1708         }
1709
1710         /**
1711          * Escape string for safe LIKE usage
1712          */
1713         function escapeLike( $s ) {
1714                 $s=$this->strencode( $s );
1715                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1716                 return $s;
1717         }
1718
1719         /**
1720          * Returns an appropriately quoted sequence value for inserting a new row.
1721          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1722          * subclass will return an integer, and save the value for insertId()
1723          */
1724         function nextSequenceValue( $seqName ) {
1725                 return NULL;
1726         }
1727
1728         /**
1729          * USE INDEX clause
1730          * PostgreSQL doesn't have them and returns ""
1731          */
1732         function useIndexClause( $index ) {
1733                 return "FORCE INDEX ($index)";
1734         }
1735
1736         /**
1737          * REPLACE query wrapper
1738          * PostgreSQL simulates this with a DELETE followed by INSERT
1739          * $row is the row to insert, an associative array
1740          * $uniqueIndexes is an array of indexes. Each element may be either a
1741          * field name or an array of field names
1742          *
1743          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1744          * However if you do this, you run the risk of encountering errors which wouldn't have
1745          * occurred in MySQL
1746          *
1747          * @todo migrate comment to phodocumentor format
1748          */
1749         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1750                 $table = $this->tableName( $table );
1751
1752                 # Single row case
1753                 if ( !is_array( reset( $rows ) ) ) {
1754                         $rows = array( $rows );
1755                 }
1756
1757                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1758                 $first = true;
1759                 foreach ( $rows as $row ) {
1760                         if ( $first ) {
1761                                 $first = false;
1762                         } else {
1763                                 $sql .= ',';
1764                         }
1765                         $sql .= '(' . $this->makeList( $row ) . ')';
1766                 }
1767                 return $this->query( $sql, $fname );
1768         }
1769
1770         /**
1771          * DELETE where the condition is a join
1772          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1773          *
1774          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1775          * join condition matches, set $conds='*'
1776          *
1777          * DO NOT put the join condition in $conds
1778          *
1779          * @param string $delTable The table to delete from.
1780          * @param string $joinTable The other table.
1781          * @param string $delVar The variable to join on, in the first table.
1782          * @param string $joinVar The variable to join on, in the second table.
1783          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1784          */
1785         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1786                 if ( !$conds ) {
1787                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1788                 }
1789
1790                 $delTable = $this->tableName( $delTable );
1791                 $joinTable = $this->tableName( $joinTable );
1792                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1793                 if ( $conds != '*' ) {
1794                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1795                 }
1796
1797                 return $this->query( $sql, $fname );
1798         }
1799
1800         /**
1801          * Returns the size of a text field, or -1 for "unlimited"
1802          */
1803         function textFieldSize( $table, $field ) {
1804                 $table = $this->tableName( $table );
1805                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1806                 $res = $this->query( $sql, 'Database::textFieldSize' );
1807                 $row = $this->fetchObject( $res );
1808                 $this->freeResult( $res );
1809
1810                 $m = array();
1811                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1812                         $size = $m[1];
1813                 } else {
1814                         $size = -1;
1815                 }
1816                 return $size;
1817         }
1818
1819         /**
1820          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1821          */
1822         function lowPriorityOption() {
1823                 return 'LOW_PRIORITY';
1824         }
1825
1826         /**
1827          * DELETE query wrapper
1828          *
1829          * Use $conds == "*" to delete all rows
1830          */
1831         function delete( $table, $conds, $fname = 'Database::delete' ) {
1832                 if ( !$conds ) {
1833                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1834                 }
1835                 $table = $this->tableName( $table );
1836                 $sql = "DELETE FROM $table";
1837                 if ( $conds != '*' ) {
1838                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1839                 }
1840                 return $this->query( $sql, $fname );
1841         }
1842
1843         /**
1844          * INSERT SELECT wrapper
1845          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1846          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1847          * $conds may be "*" to copy the whole table
1848          * srcTable may be an array of tables.
1849          */
1850         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1851                 $insertOptions = array(), $selectOptions = array() )
1852         {
1853                 $destTable = $this->tableName( $destTable );
1854                 if ( is_array( $insertOptions ) ) {
1855                         $insertOptions = implode( ' ', $insertOptions );
1856                 }
1857                 if( !is_array( $selectOptions ) ) {
1858                         $selectOptions = array( $selectOptions );
1859                 }
1860                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1861                 if( is_array( $srcTable ) ) {
1862                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1863                 } else {
1864                         $srcTable = $this->tableName( $srcTable );
1865                 }
1866                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1867                         " SELECT $startOpts " . implode( ',', $varMap ) .
1868                         " FROM $srcTable $useIndex ";
1869                 if ( $conds != '*' ) {
1870                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1871                 }
1872                 $sql .= " $tailOpts";
1873                 return $this->query( $sql, $fname );
1874         }
1875
1876         /**
1877          * Construct a LIMIT query with optional offset
1878          * This is used for query pages
1879          * $sql string SQL query we will append the limit too
1880          * $limit integer the SQL limit
1881          * $offset integer the SQL offset (default false)
1882          */
1883         function limitResult($sql, $limit, $offset=false) {
1884                 if( !is_numeric($limit) ) {
1885                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1886                 }
1887                 return " $sql LIMIT "
1888                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1889                                 . "{$limit} ";
1890         }
1891         function limitResultForUpdate($sql, $num) {
1892                 return $this->limitResult($sql, $num, 0);
1893         }
1894
1895         /**
1896          * Returns an SQL expression for a simple conditional.
1897          * Uses IF on MySQL.
1898          *
1899          * @param string $cond SQL expression which will result in a boolean value
1900          * @param string $trueVal SQL expression to return if true
1901          * @param string $falseVal SQL expression to return if false
1902          * @return string SQL fragment
1903          */
1904         function conditional( $cond, $trueVal, $falseVal ) {
1905                 return " IF($cond, $trueVal, $falseVal) ";
1906         }
1907
1908         /**
1909          * Determines if the last failure was due to a deadlock
1910          */
1911         function wasDeadlock() {
1912                 return $this->lastErrno() == 1213;
1913         }
1914
1915         /**
1916          * Perform a deadlock-prone transaction.
1917          *
1918          * This function invokes a callback function to perform a set of write
1919          * queries. If a deadlock occurs during the processing, the transaction
1920          * will be rolled back and the callback function will be called again.
1921          *
1922          * Usage:
1923          *   $dbw->deadlockLoop( callback, ... );
1924          *
1925          * Extra arguments are passed through to the specified callback function.
1926          *
1927          * Returns whatever the callback function returned on its successful,
1928          * iteration, or false on error, for example if the retry limit was
1929          * reached.
1930          */
1931         function deadlockLoop() {
1932                 $myFname = 'Database::deadlockLoop';
1933
1934                 $this->begin();
1935                 $args = func_get_args();
1936                 $function = array_shift( $args );
1937                 $oldIgnore = $this->ignoreErrors( true );
1938                 $tries = DEADLOCK_TRIES;
1939                 if ( is_array( $function ) ) {
1940                         $fname = $function[0];
1941                 } else {
1942                         $fname = $function;
1943                 }
1944                 do {
1945                         $retVal = call_user_func_array( $function, $args );
1946                         $error = $this->lastError();
1947                         $errno = $this->lastErrno();
1948                         $sql = $this->lastQuery();
1949
1950                         if ( $errno ) {
1951                                 if ( $this->wasDeadlock() ) {
1952                                         # Retry
1953                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1954                                 } else {
1955                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1956                                 }
1957                         }
1958                 } while( $this->wasDeadlock() && --$tries > 0 );
1959                 $this->ignoreErrors( $oldIgnore );
1960                 if ( $tries <= 0 ) {
1961                         $this->query( 'ROLLBACK', $myFname );
1962                         $this->reportQueryError( $error, $errno, $sql, $fname );
1963                         return false;
1964                 } else {
1965                         $this->query( 'COMMIT', $myFname );
1966                         return $retVal;
1967                 }
1968         }
1969
1970         /**
1971          * Do a SELECT MASTER_POS_WAIT()
1972          *
1973          * @param string $file the binlog file
1974          * @param string $pos the binlog position
1975          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1976          */
1977         function masterPosWait( $file, $pos, $timeout ) {
1978                 $fname = 'Database::masterPosWait';
1979                 wfProfileIn( $fname );
1980
1981
1982                 # Commit any open transactions
1983                 $this->immediateCommit();
1984
1985                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1986                 $encFile = $this->strencode( $file );
1987                 $sql = "SELECT MASTER_POS_WAIT('$encFile', $pos, $timeout)";
1988                 $res = $this->doQuery( $sql );
1989                 if ( $res && $row = $this->fetchRow( $res ) ) {
1990                         $this->freeResult( $res );
1991                         wfProfileOut( $fname );
1992                         return $row[0];
1993                 } else {
1994                         wfProfileOut( $fname );
1995                         return false;
1996                 }
1997         }
1998
1999         /**
2000          * Get the position of the master from SHOW SLAVE STATUS
2001          */
2002         function getSlavePos() {
2003                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
2004                 $row = $this->fetchObject( $res );
2005                 if ( $row ) {
2006                         return array( $row->Master_Log_File, $row->Read_Master_Log_Pos );
2007                 } else {
2008                         return array( false, false );
2009                 }
2010         }
2011
2012         /**
2013          * Get the position of the master from SHOW MASTER STATUS
2014          */
2015         function getMasterPos() {
2016                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
2017                 $row = $this->fetchObject( $res );
2018                 if ( $row ) {
2019                         return array( $row->File, $row->Position );
2020                 } else {
2021                         return array( false, false );
2022                 }
2023         }
2024
2025         /**
2026          * Begin a transaction, committing any previously open transaction
2027          */
2028         function begin( $fname = 'Database::begin' ) {
2029                 $this->query( 'BEGIN', $fname );
2030                 $this->mTrxLevel = 1;
2031         }
2032
2033         /**
2034          * End a transaction
2035          */
2036         function commit( $fname = 'Database::commit' ) {
2037                 $this->query( 'COMMIT', $fname );
2038                 $this->mTrxLevel = 0;
2039         }
2040
2041         /**
2042          * Rollback a transaction
2043          */
2044         function rollback( $fname = 'Database::rollback' ) {
2045                 $this->query( 'ROLLBACK', $fname );
2046                 $this->mTrxLevel = 0;
2047         }
2048
2049         /**
2050          * Begin a transaction, committing any previously open transaction
2051          * @deprecated use begin()
2052          */
2053         function immediateBegin( $fname = 'Database::immediateBegin' ) {
2054                 $this->begin();
2055         }
2056
2057         /**
2058          * Commit transaction, if one is open
2059          * @deprecated use commit()
2060          */
2061         function immediateCommit( $fname = 'Database::immediateCommit' ) {
2062                 $this->commit();
2063         }
2064
2065         /**
2066          * Return MW-style timestamp used for MySQL schema
2067          */
2068         function timestamp( $ts=0 ) {
2069                 return wfTimestamp(TS_MW,$ts);
2070         }
2071
2072         /**
2073          * Local database timestamp format or null
2074          */
2075         function timestampOrNull( $ts = null ) {
2076                 if( is_null( $ts ) ) {
2077                         return null;
2078                 } else {
2079                         return $this->timestamp( $ts );
2080                 }
2081         }
2082
2083         /**
2084          * @todo document
2085          */
2086         function resultObject( $result ) {
2087                 if( empty( $result ) ) {
2088                         return false;
2089                 } elseif ( $result instanceof ResultWrapper ) {
2090                         return $result;
2091                 } elseif ( $result === true ) {
2092                         // Successful write query
2093                         return $result;
2094                 } else {
2095                         return new ResultWrapper( $this, $result );
2096                 }
2097         }
2098
2099         /**
2100          * Return aggregated value alias
2101          */
2102         function aggregateValue ($valuedata,$valuename='value') {
2103                 return $valuename;
2104         }
2105
2106         /**
2107          * @return string wikitext of a link to the server software's web site
2108          */
2109         function getSoftwareLink() {
2110                 return "[http://www.mysql.com/ MySQL]";
2111         }
2112
2113         /**
2114          * @return string Version information from the database
2115          */
2116         function getServerVersion() {
2117                 return mysql_get_server_info( $this->mConn );
2118         }
2119
2120         /**
2121          * Ping the server and try to reconnect if it there is no connection
2122          */
2123         function ping() {
2124                 if( function_exists( 'mysql_ping' ) ) {
2125                         return mysql_ping( $this->mConn );
2126                 } else {
2127                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
2128                         return true;
2129                 }
2130         }
2131
2132         /**
2133          * Get slave lag.
2134          * At the moment, this will only work if the DB user has the PROCESS privilege
2135          */
2136         function getLag() {
2137                 $res = $this->query( 'SHOW PROCESSLIST' );
2138                 # Find slave SQL thread
2139                 while ( $row = $this->fetchObject( $res ) ) {
2140                         /* This should work for most situations - when default db
2141                          * for thread is not specified, it had no events executed,
2142                          * and therefore it doesn't know yet how lagged it is.
2143                          *
2144                          * Relay log I/O thread does not select databases.
2145                          */
2146                         if ( $row->User == 'system user' &&
2147                                 $row->State != 'Waiting for master to send event' &&
2148                                 $row->State != 'Connecting to master' &&
2149                                 $row->State != 'Queueing master event to the relay log' &&
2150                                 $row->State != 'Waiting for master update' &&
2151                                 $row->State != 'Requesting binlog dump'
2152                                 ) {
2153                                 # This is it, return the time (except -ve)
2154                                 if ( $row->Time > 0x7fffffff ) {
2155                                         return false;
2156                                 } else {
2157                                         return $row->Time;
2158                                 }
2159                         }
2160                 }
2161                 return false;
2162         }
2163
2164         /**
2165          * Get status information from SHOW STATUS in an associative array
2166          */
2167         function getStatus($which="%") {
2168                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
2169                 $status = array();
2170                 while ( $row = $this->fetchObject( $res ) ) {
2171                         $status[$row->Variable_name] = $row->Value;
2172                 }
2173                 return $status;
2174         }
2175
2176         /**
2177          * Return the maximum number of items allowed in a list, or 0 for unlimited.
2178          */
2179         function maxListLen() {
2180                 return 0;
2181         }
2182
2183         function encodeBlob($b) {
2184                 return $b;
2185         }
2186
2187         function decodeBlob($b) {
2188                 return $b;
2189         }
2190
2191         /**
2192          * Override database's default connection timeout.
2193          * May be useful for very long batch queries such as
2194          * full-wiki dumps, where a single query reads out
2195          * over hours or days.
2196          * @param int $timeout in seconds
2197          */
2198         public function setTimeout( $timeout ) {
2199                 $this->query( "SET net_read_timeout=$timeout" );
2200                 $this->query( "SET net_write_timeout=$timeout" );
2201         }
2202
2203         /**
2204          * Read and execute SQL commands from a file.
2205          * Returns true on success, error string on failure
2206          * @param string $filename File name to open
2207          * @param callback $lineCallback Optional function called before reading each line
2208          * @param callback $resultCallback Optional function called for each MySQL result
2209          */
2210         function sourceFile( $filename, $lineCallback = false, $resultCallback = false ) {
2211                 $fp = fopen( $filename, 'r' );
2212                 if ( false === $fp ) {
2213                         return "Could not open \"{$filename}\".\n";
2214                 }
2215                 $error = $this->sourceStream( $fp, $lineCallback, $resultCallback );
2216                 fclose( $fp );
2217                 return $error;
2218         }
2219
2220         /**
2221          * Read and execute commands from an open file handle
2222          * Returns true on success, error string on failure
2223          * @param string $fp File handle
2224          * @param callback $lineCallback Optional function called before reading each line
2225          * @param callback $resultCallback Optional function called for each MySQL result
2226          */
2227         function sourceStream( $fp, $lineCallback = false, $resultCallback = false ) {
2228                 $cmd = "";
2229                 $done = false;
2230                 $dollarquote = false;
2231
2232                 while ( ! feof( $fp ) ) {
2233                         if ( $lineCallback ) {
2234                                 call_user_func( $lineCallback );
2235                         }
2236                         $line = trim( fgets( $fp, 1024 ) );
2237                         $sl = strlen( $line ) - 1;
2238
2239                         if ( $sl < 0 ) { continue; }
2240                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
2241
2242                         ## Allow dollar quoting for function declarations
2243                         if (substr($line,0,4) == '$mw$') {
2244                                 if ($dollarquote) {
2245                                         $dollarquote = false;
2246                                         $done = true;
2247                                 }
2248                                 else {
2249                                         $dollarquote = true;
2250                                 }
2251                         }
2252                         else if (!$dollarquote) {
2253                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
2254                                         $done = true;
2255                                         $line = substr( $line, 0, $sl );
2256                                 }
2257                         }
2258
2259                         if ( '' != $cmd ) { $cmd .= ' '; }
2260                         $cmd .= "$line\n";
2261
2262                         if ( $done ) {
2263                                 $cmd = str_replace(';;', ";", $cmd);
2264                                 $cmd = $this->replaceVars( $cmd );
2265                                 $res = $this->query( $cmd, __METHOD__, true );
2266                                 if ( $resultCallback ) {
2267                                         call_user_func( $resultCallback, $res );
2268                                 }
2269
2270                                 if ( false === $res ) {
2271                                         $err = $this->lastError();
2272                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2273                                 }
2274
2275                                 $cmd = '';
2276                                 $done = false;
2277                         }
2278                 }
2279                 return true;
2280         }
2281
2282
2283         /**
2284          * Replace variables in sourced SQL
2285          */
2286         protected function replaceVars( $ins ) {
2287                 $varnames = array(
2288                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2289                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2290                         'wgDBadminuser', 'wgDBadminpassword', 'wgDBTableOptions',
2291                 );
2292
2293                 // Ordinary variables
2294                 foreach ( $varnames as $var ) {
2295                         if( isset( $GLOBALS[$var] ) ) {
2296                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2297                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2298                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2299                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2300                         }
2301                 }
2302
2303                 // Table prefixes
2304                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-z_]*)/',
2305                         array( &$this, 'tableNameCallback' ), $ins );
2306                 return $ins;
2307         }
2308
2309         /**
2310          * Table name callback
2311          * @private
2312          */
2313         protected function tableNameCallback( $matches ) {
2314                 return $this->tableName( $matches[1] );
2315         }
2316
2317         /*
2318          * Build a concatenation list to feed into a SQL query
2319         */
2320         function buildConcat( $stringList ) {
2321                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2322         }
2323
2324 }
2325
2326 /**
2327  * Database abstraction object for mySQL
2328  * Inherit all methods and properties of Database::Database()
2329  *
2330  * @addtogroup Database
2331  * @see Database
2332  */
2333 class DatabaseMysql extends Database {
2334         # Inherit all
2335 }
2336
2337
2338 /**
2339  * Result wrapper for grabbing data queried by someone else
2340  * @addtogroup Database
2341  */
2342 class ResultWrapper implements Iterator {
2343         var $db, $result, $pos = 0, $currentRow = null;
2344
2345         /**
2346          * Create a new result object from a result resource and a Database object
2347          */
2348         function ResultWrapper( $database, $result ) {
2349                 $this->db = $database;
2350                 if ( $result instanceof ResultWrapper ) {
2351                         $this->result = $result->result;
2352                 } else {
2353                         $this->result = $result;
2354                 }
2355         }
2356
2357         /**
2358          * Get the number of rows in a result object
2359          */
2360         function numRows() {
2361                 return $this->db->numRows( $this->result );
2362         }
2363
2364         /**
2365          * Fetch the next row from the given result object, in object form.
2366          * Fields can be retrieved with $row->fieldname, with fields acting like
2367          * member variables.
2368          *
2369          * @param $res SQL result object as returned from Database::query(), etc.
2370          * @return MySQL row object
2371          * @throws DBUnexpectedError Thrown if the database returns an error
2372          */
2373         function fetchObject() {
2374                 return $this->db->fetchObject( $this->result );
2375         }
2376
2377         /**
2378          * Fetch the next row from the given result object, in associative array
2379          * form.  Fields are retrieved with $row['fieldname'].
2380          *
2381          * @param $res SQL result object as returned from Database::query(), etc.
2382          * @return MySQL row object
2383          * @throws DBUnexpectedError Thrown if the database returns an error
2384          */
2385         function fetchRow() {
2386                 return $this->db->fetchRow( $this->result );
2387         }
2388
2389         /**
2390          * Free a result object
2391          */
2392         function free() {
2393                 $this->db->freeResult( $this->result );
2394                 unset( $this->result );
2395                 unset( $this->db );
2396         }
2397
2398         /**
2399          * Change the position of the cursor in a result object
2400          * See mysql_data_seek()
2401          */
2402         function seek( $row ) {
2403                 $this->db->dataSeek( $this->result, $row );
2404         }
2405
2406         /*********************
2407          * Iterator functions
2408          * Note that using these in combination with the non-iterator functions
2409          * above may cause rows to be skipped or repeated.
2410          */
2411
2412         function rewind() {
2413                 if ($this->numRows()) {
2414                         $this->db->dataSeek($this->result, 0);
2415                 }
2416                 $this->pos = 0;
2417                 $this->currentRow = null;
2418         }
2419
2420         function current() {
2421                 if ( is_null( $this->currentRow ) ) {
2422                         $this->next();
2423                 }
2424                 return $this->currentRow;
2425         }
2426
2427         function key() {
2428                 return $this->pos;
2429         }
2430
2431         function next() {
2432                 $this->pos++;
2433                 $this->currentRow = $this->fetchObject();
2434                 return $this->currentRow;
2435         }
2436
2437         function valid() {
2438                 return $this->current() !== false;
2439         }
2440 }
2441
2442